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Advanced Healthcare Statistics
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Terms in this set (170)
The equation Σxi∧2 is best known as the:
A. The sum of all the squared values of the variable x in the data set
B. Product of all the values of the variable x in the data set
C. Square of the sum of all the values of the variable x in the data set
A
The equation (Σxi)2 is best known as the:
A. Sum of all the squared values of the variable x in the data set
B. Product of all the values of the variable x in the data set
C. Square of the sum of all the values of the variable x in the data set
D. Sum of all the values of the variable x in the data set
C
A nominal level of measurement is used when the values of a variable have which of the following properties?
A. They an be placed in meaningful order, but there is no information about the size of the interval between each value.
B. They can be placed in meaningful order,have meaningful intervals, and have a true zero.
C. They can be placed in meaningful order and have meaningful intervals between the times, but there is no true zero.
D. They simply represent categories
D
Class intervals should be:
A. Of equal length
B. Mutually exclusive
C. Overlapping intervals
D. A and B only
D
Symmetrical distributions are best described by which of the following statements?
A. They have an equal number of data points that appear to the left and right of the center
B. They are normally distributed
C. They have a U-shaped distribution
D. They have a standard deviation
A
Skewness refers to the :
A. Shape of the top of the curve
B. Extent to which data are not symmetrical
C. Presence of outliers
D. Sample
B
Which of the following statements best describes a stem-and-leaf display?
a. It shows the range of values of the variable.
b. It shows the shape of the distribution of the variable.
c. It preserves the individual values of the variable.
d. All of the above are correct
D
Standard deviation is best described by which of the following statements?
a. It can be used to compare variation between two or more variables.
b. It is the average distance of each point from the mean.
c. It is the variance squared.
d. Both a and b are correct
B
Descriptive statistics have which of the following properties?
a. They are numerical or graphical summaries of data.
b. They are used to examine relationships between variables in a data set.
c. They are used to see how well sample data can be generalized to the population.
d. All of these.
A
Inferential statistics have which of the following properties?
a. They are numerical or graphical summaries of data.
b. They are used to examine relationships between variables in a data set.
c. They are used to see how well sample data can be generalized to the population.
d. Both b and c are correct
D
The p(A) is most accurately defined as the:
A. Joint probability of event A
B. Marginal probability of event A
C. Proof of event A
D. Marginal probability that event A will not occur
B
The p(B) is most accurately defined as the:
A. Joint probability of event B
B. Marginal probability of event B
C. Proof of event B
D. Marginal probability that event B will not occur
D
The p(B]A) is most accurately defined as the:
A. Joint probability that events A and B will occur
B. Addition rule
C. Conditional probability that event B will occur
D. Multiplication rule
C
The p(AŬB)=p(A)+p(B)-p(AΠB) describes the:
A. Joint probability that events A and B will occur
B. Addition rule
C. Conditional probability that event B will occur
D. Multiplication rule
B
If the p(A | B) = p(A), then
a. two events are independent.
b. two events are mutually exclusive.
c. p(A) = p(B).
d. none of the above apply
A
A normal distribution is characterized by a.
a bell shape.
b. a mean, median, and mode that are equal.
c. a total area under the curve above the x-axis that is 1.
d. all of the above
D
A z-score can give information about
a. the mean of a distribution.
b. the standard deviation (SD) of a distribution.
c. the percentile rank of a data point.
d. none of the above
C
A z-score of 0 corresponds to the
a. mean.
b. SD.
c. interquartile range.
d. 75th percentile
A
The 50th percentile is always the
A. Mean
B. Median
C. SD
D. A and B
B
A sample population cure is more likely to look like the population curve when:
A. The bell shape is wide
B. The sample size is small
C. The sample size is >30
D. None of the above
C
The null hypothesis states:
A. The expected direction of the relationship between the variables.
B. That no relationship will be found
C. That a relationship will be found, but it will not state the direction
D. None of the above
B
The a-level is defined by:
A. The probability of making a Type I error
B. The probability of making a Type II error
C. The researcher at the start of a study
D. A and C only
C
The one sample t-test is used to compare a sample mean to a population mean when:
A. The population mean is known
B. The population standard deviation (SD) is not known
C. The sample size is at least 30
D. All of the above occur
B
Power is defined by
a. the α-level.
b. the sample size.
c. the effect size (γ).
d. all of the above
D
A type I error occurs when the
a. null hypothesis is accepted when it is false.
b. null hypothesis is rejected when it is true.
c. sample size is too small.
d. effect size (γ) is not defined in advance
B
A type II error occurs when the
a. null hypothesis is accepted when it is false.
b. null hypothesis is rejected when it is true.
c. sample size is too small.
d. effect size (γ) is not defined in advance
A
Power can be increased by doing which of the following?
a. Increasing the α-level.
b. Increasing the sample size.
c. Increasing the effect size (γ).
d. All of the above.
D
A researcher conducts a small study and finds that no statistically significant relationship exists between smoking and lung cancer. This is most likely a.
a type I error.
b. a type II error.
c. both a and b.
d. none of the above
B
Which of the following is more likely to contain the "true" population value of the mean?
a. A 90% confidence interval (CI).
b. A 95% CI.
c. A 99% CI.
d. All of the above
C
If a statistical test is significant, it means that
a. it has important clinical applications.
b. the study had acceptable power.
c. the null hypothesis was rejected.
d. all of the above are true
C
The Pearson correlation test is best described as a.
a type of ANOVA.
b. a parametric test.
c. a nonparametric test.
d. none of the above
B
The Pearson correlation coefficient is best used to determine the association of
a. two ratio variables to each other.
b. three or more ratio variables to each other.
c. two nominal variables to each other.
d. three or more ordinal variables to each other
A
The Pearson correlation coefficient is most appropriate to use when
a. neither of the variables is normally distributed.
b. one of the variables is normally distributed.
c. both of the variables are normally distributed.
d. none of the above
C
The Pearson correlation coefficient provides a measure of
a. U-shaped relationships.
b. the strength of curvilinear relationships.
c. the strength of linear relationships.
d. all of the above.
C
Correlation coefficients measure
a. positive relationships.
b. inverse relationships.
c. curvilinear relationships.
d. a and b only
D
The Spearman correlation coefficient is best used to examine the relationship of
a. three or more ratio variables to each other.
b. two nonnormally distributed ordinal or interval or ratio variables to each other.
c. two nominal variables to each other.
d. a nominal variable to a ratio variable
B
The Spearman correlation coefficient should be used instead of the Pearson correlation coefficient when
a. neither of the variables is normally distributed.
b. one of the variables is normally distributed.
c. both of the variables are normally distributed.
d. both a and b.
D
A perfect inverse relationship would have an r of
a. −1.
b. 0.
c. +1.
d. 100.
A
The r2
a. the variance not shared by the two variables.
b. strength of the positive relationship of the two variables.
c. the variance shared by the two variables.
d. none of the above
measures
C
The Pearson and Spearman correlation coefficients can be used to measure
a. the relationship of two independent variables to each other.
b. the relationship of two related variables to each other.
c. test-retest reliability.
d. all of the above
D
Multiple linear regression models are best used with
a. a dichotomous dependent variable.
b. any ratio-level variable.
c. a normally distributed ratio-level variable.
d. all of the above
C
The un-adjusted regression coefficients (bs) in a multiple linear regression model give information about
a. the strongest predictor of the dependent variable.
b. the change in the dependent variable per unit increase in the independent variable.
c. the adjusted odds of having the condition represented by the dependent variable given that the independent variable is present.
d. a and b only
B
The adjusted regression coefficient in a multiple linear regression contains information about
a. the strongest predictor of the dependent variable.
b. the change in the dependent variable per unit increase in the independent variable.
c. the adjusted odds of having the condition represented by the dependent variable given that the independent variable is present.
d. a and b only.
A
The coefficient of determination in a multiple linear regression contains information about
a. the strongest predictor of the dependent variable.
b. the change in the dependent variable per unit increase in the independent variable.
c. the adjusted odds of having the condition represented by the dependent variable given that the independent variable is present.
d. the amount of variance in the dependent variable explained by the model
D
Linear regression models describe
a. curvilinear relationships only.
b. linear relationships only.
c. both a and b.
d. none of the above
B
Dummy variables are used to
a. recode the dependent variable.
b. represent ratio variables in regression models.
c. represent ordinal variables in regression models.
d. represent nominal variables in regression models
D
Linear regression allows you to test the significance of the following:
a. The overall model
b. Each regression coefficient
c. The risk ratio comparing those with a characteristic to those without
d. a and b only
D
When the outcome is nominal and dichotomous, which form of regression would be appropriate?
a. Linear regression
b. Logistic regression
c. Multinomial or polytomous regression
d. All of the above
B
Multivariate regression models, be they linear, logistic, or any other form, allow us to do which of the following?
a. Simultaneously consider the effects of several independent variables on the dependent variable of interest
b. Look at the association between two variables of nominal scale
c. Minimize the risk of obtaining spurious results
d. a and c
D
Adding an interaction term to the linear regression model allows us to
a. interpret the adjusted association between each independent variable and the outcome.
b. assess whether there is significant interaction between the two variables used to create the interaction term.
c. calculate odds ratios.
d. all of the above
B
How would you interpret a correlation coefficient of -1?
A) Strong positive correlation - as one variable increases, so does the other
B) Weak negative correlation - as one variable increases, the other variable decreases slightly
C) No correlation at all
D) Perfect negative correlation - as one variable increases, the other variable decreases
D
A study looking at the correlation between cholesterol level and distance between home and work found a correlation coefficient of ¿0.13. How much of the variance in cholesterol level is explained by distance between home and work (ie, what is the coefficient of determination)?
A) 13%
B) 1.7%
C) 0.13%
D) 0.17%
B
Which of the following are assumptions required for the Pearson correlation coefficient to be valid?
A) The two variables must have a linear relationship.
B) Homoscedasticity
C) The two variables must be of interval or ratio measurement scale.
D) The two variables must be normally distributed.
E) The two variables must be of ordinal, interval, or ratio measurement scale.
F) There are no outliers
A,B,C,D,F
Under which of the following conditions would you need to use the Spearman correlation coefficient and not the Pearson correlation coefficient?
A) The two variables are normally distributed.
B) The two variables do not have a linear relationship.
C) One variable on the ordinal measurement scale and one is on the interval measurement scale.
D) There are only three outliers.
E) Neither variable is normally distributed.
F) There is only one variable to be examined
B,C,D,E
A study was conducted looking at the association between number of polyps in the colon and mean grams of fiber consumed per day based on a standard food frequency questionnaire. The Pearson correlation coefficient was 0.9 with a p-value of 0.003 and the Spearman correlation coefficient was 0.28 with a p-value of 0.049. Which form of correlation would be more appropriate to report and why?
A) The Pearson correlation results should be reported because it shows a stronger correlation with a smaller p-value (more significant).
B) The Pearson correlation results should be reported because the two variables are normally distributed.
C) The Spearman correlation results should be reported because at least one of the variables does not meet the distribution assumption required to use Pearson correlation.
D) The Spearman correlation results should be reported because the p-value is closer to 0.05
C
In a study looking at the correlation between annual income and cholesterol level, one concern was that the age of the participants might be a confounder because both income and cholesterol generally increase with age. Which of the following correlation methods could the researchers use to remove the influence of age on the correlation between income and cholesterol level?
A) Kendall's Tau
B) Spearman correlation coefficient
C) Partial correlation
D) Point-Biserial
C
Squaring the Pearson correlation coefficient (r2) tells us that
A) the direction of the association (positive or negative).
B) whether the correlation is statistically significant at the 0.05 level.
C) how much variance is shared by the two variables.
D) whether or not we need to conduct a Spearman test of correlation instead
C
One of the important benefits of multivariate regression over many other statistical tests is that it
A) allows you to prevent measurement error.
B) ascertains temporal order that is necessary for causal inference.
C) ensures that you are fulfilling all the required assumptions for statistical testing.
D) allows you to adjust for potentially confounding variables
D
What type of relationship between a dependent and independent variable is described by linear regression?
A) An exponential relationship
B) A parabolic relationship
C) A linear relationship
D) A threshold effect
C
Linear regression is appropriate for what type of dependent variable?
A) Ratio scale and normally distributed
B) Count
C) Dichotomous
D) Polytomous
A
In a study looking at the association of mean hours worked per day (hours) and age (years) with body mass index (BMI), the researchers used multivariate liner regression. The regression equation is below. What BMI would you predict from this equation for someone age 25 years who works 45 hours per week?
Y = -3.95 + 0.04(hours worked) + 1.21(age)
A) 32.05
B) 28.1
C) -2.7
D) 66.05
B
What measure(s) of the strength and direction of association can we get from a linear regression model? (Select all that apply.)
A) One-way ANOVA
B) Chi-square
C) Risk ratio
D) Odds ratio
E) Regression coefficient (beta)
F) F-statistic
E
A multivariate regression model looking at the association of intraocular pressure (mm hg) with (1) having seasonal allergies, (2) wearing contact lenses, and (3) using eye drops found a coefficient of determination (r2) of 0.23. How would you interpret this statistic?
A) The association between having seasonal allergies, use of contact lenses, and use of eye drops with intraocular pressure is not significant at the 0.05 level.
B) The intraocular eye pressure of those who have seasonal allergies is 0.23 mm hg higher compared to those without allergies, adjusting for use of contact lenses and eye drops.
C) Those who wear contact lenses, have seasonal allergies, and use eye drops have a 37% chance of having high intraocular pressure.
D) seasonal allergies, contact lens use, and eye drop use taken together explain 23% of the variation in intraocular eye pressure
D
What do we mean by ¿regression toward the mean?
A) The linear regression equation can be used to identify the average value of each variable in the model.
B) The phenomenon that if a variable is extreme on its first measurement, it will tend to be closer to the average on a second measurement.
C) Linear regression normalizes the scale of the variables so they have a mean of zero and standard deviation of 1.
D) Outliers in the model should always be excluded when using linear regression
B
A strong correlation (>0.85) between the independent variables that you want to include in one multivariate linear regression model is an indication that which assumption has been violated?
A) Multicolinearity
B) Residual analysis
C) Homoscedasticity
D) Normal distribution of the dependent variable
A
What is the difference between stepwise methods versus the standard approach and hierarchical methods of selecting independent variables to include in a linear regression model?
A) Stepwise uses theoretical rational, whereas the other approaches use statistical criteria for selecting the variables for inclusion.
B) Stepwise methods allow you to include more variables without increasing the probability of making a type I error.
C) Stepwise uses statistical criteria for selecting the variables to be included, whereas the other approaches use theoretical rational.
D) Stepwise is better for hypothesis testing than the other approaches because it is less influenced by chance
C
Health care practices have improved due in part to the use of
A) experimentation.
B) observation.
C) systemic review of research evidence.
D) trial-and-error
C
One response to the nursing shortage has resulted in the recruitment of nurses with various educational levels. The results of one research study found that the level of nursing education is critical in caring for certain patients. Therefore, we can conclude that
A) proper education results in better patient care.
B) increasing the number of nurses without concern for educational level has serious implications for critically ill patients.
C) proper mentoring will ensure the nursing staff is well prepared.
D) on-the-job training will provide adequate exposure to proper nursing techniques for all levels of patients
B
Simple numerical or graphical summaries are referred to as
A) explanation statistics.
B) inferential statistics.
C) control statistics.
D) descriptive statistics
D
Techniques that allow conclusions to be drawn about the relationships found among different variables in a population sample are referred to as
A) descriptive statistics.
B) inferential statistics.
C) predictive statistics.
D) explanatory statistics
B
A study that often attempts to understand how variables are related to each other is referred to as
A) predictive studies.
B) explanatory studies.
C) inferential statistics.
D) descriptive statistics
B
A research study needs to be well planned before starting. A common mistake seen in research is
A) reviewing existing literature on the subject.
B) developing a detailed study plan.
C) defining general and ambiguous terms or language.
D) failing to recognize approach limitations
D
The study plan hypotheses
A) will be changed as the study evolves.
B) must be very specific.
C) can be decided after the data are collected.
D) can be generalized
B
The hypotheses of the study should
A) be based on expert opinion.
B) state the expected relationship between the variables.
C) be updated at the end of the study.
D) predetermine the study results
B
A research project that follows the participants forward in time to identify future outcomes is referred to as
A) a quasi-experimental.
B) a cohort study.
C) a cross-sectional.
D) a case¿control study
B
When defining a good research study, which of the following should be included?
A) Description of the sample and how it was obtained
B) List of the hypotheses to be tested
C) Statement of the problem
D) Description of the planned statistical analysis
E) The expected outcome
A,B,C,D
A pediatrician will compare the 6-week-old infant with the accepted normal growth progress using the
A) percentile rank.
B) nominal scale.
C) frequency table.
D) stemplots.
A
Commonly used techniques of presenting and organizing statistical data include which of the following?
A) Graphical displays
B) Frequency distributions
C) Summary charts
D) Descriptive statistics
A,B,D
The first step to deciding which statistical technique to use is
A) to identify the question to be answered.
B) to determine the hypotheses.
C) to identify the variables.
D) to determine which measurement scale to use
A
The proper graph to demonstrate the following research data would be
Weight Range Raw Frequency
100¿119 2
120¿139 4
140¿159 5
160¿179 6
180¿199 11
200¿219 4
220¿239 3
A) histogram.
B) pie chart.
C) stem-and-leaf plot.
D) flow chart
A
Data values that do not fit the pattern of the rest of the data are
A) deleted from the study.
B) considered outliers.
C) reinvestigated.
D) put in a separate category
B
The marginal probability is computed by
A) the total number of times that the event could have occurred divided by the number of times the event occurred.
B) the number of times the event occurred divided by the total number of times that it could have occurred.
C) dividing the subset by the total number of times and then multiplying by 100.
D) subtracting the number of times the event occurred from 100 and then dividing by the total number of times that it could have occurred
B
The set of probabilities associated with each possible outcome in the sample space is referred to as
A) t distribution.
B) marginal distribution.
C) probability distribution.
D) conditional distribution
C
The normal distribution is a frequency polygon that demonstrates which of the following properties?
A) Bell shaped
B) The population mean is shown as .
C) Mean, median, and mode are equal.
D) Total area under the curve above the x-axis equals 1
A,C,D
The _____ of a test is the probability that the test result and the diagnosis agree.
A) sensitivity.
B) specificity.
C) predictive value.
D) efficiency
D
Confidence intervals can be computed around the population mean from a single simple mean using the
A) central limit theorem.
B) normal distribution.
C) predictive value.
D) joint probability
A
. ________ probability is the probability that one event will occur given that another event has occurred.
A) Joint
B) Conditional
C) Marginal
D) Addition
B
The process for testing hypotheses includes which of the following?
A) Make sure the data meet the necessary assumptions to compute the test statistic.
B) Obtain the p-value of computed statistic.
C) Define significance level.
D) Compute the parameters that are being compared by the test statistic.
E) Compute the test statistic
A,B,C,D,E
The local health department is interested in determining if there is a difference in the incidence of childhood caries among children living in rural areas drinking untreated well water and children living in cities drinking fluorinated water. A null hypothesis could read
A) the oral health of the rural children will be significantly worse than that of the city children.
B) the oral health of the city children will be significantly worse than that of the rural children.
C) the oral health of the city children will be significantly better than that of the rural children.
D) the oral health of the rural children will not differ from that of the city children
D
The alpha-level is defined by the researcher before any statistical tests are conducted. This specific level is defined as
A) the p-value.
B) the standard deviation.
C) error of inference.
D) statistically significant
D
The researcher has determined the project has an = 0.05. This indicates all values outside ____ will be rejected.
A) 45%
B) 55%
C) 75%
D) 95%
D
A null hypothesis was not rejected, and later it was found that the results were false. This is an example of
A) a type I error.
B) a type II error.
C) a type III error.
D) a type IV error
B
A potential mistake when interpreting the data is to reject the H0 when it is true. This is referred to as
A) a type I error.
B) a type II error.
C) a type III error.
D) a type IV error
A
Researchers articulate the expected relationships between the variables by the _______.
A) null hypothesis
B) alternative hypothesis
C) parameters
D) statistic
A
1.
Data values that do not fit the pattern of the rest of the data are
A)reinvestigated.
B)put in a separate category.
C)considered outliers.
D)deleted from the study
c
A strong correlation (>0.85) between the independent variables that you want to include in one multivariate linear regression model is an indication that which assumption has been violated?
A)Normal distribution of the dependent variable
B)Residual analysis
C)Multicolinearity
D)Homoscedasticity
c
Commonly used techniques of presenting and organizing statistical data include which of the following?
A)Descriptive statistics
B)Graphical displays
C)Frequency distributions
D)Summary charts
abc
A psychologist is interested in learning how well his clients are doing with a certain treatment. He asks his clients to complete the following survey. The data collected will be used to create
After taking the medication, I feel
0Depressed after 15 hours
1Depressed after 10 hours
2Depressed after 5 hours
3No change
A)an interval scale.
B)a ratio scale.
C)a summary scale.
D)an ordinal scale
a
The set of probabilities associated with each possible outcome in the sample space is referred to as
A)probability distribution.
B)t distribution.
C)conditional distribution.
D)marginal distribution
A
A null hypothesis was not rejected, and later it was found that the results were false. This is an example of
A)a type IV error.
B)a type III error.
C)a type I error.
D)a type II error.
D
One of the important benefits of multivariate regression over many other statistical tests is that it
A)ensures that you are fulfilling all the required assumptions for statistical testing.
B)allows you to adjust for potentially confounding variables.
C)allows you to prevent measurement error.
D)ascertains temporal order that is necessary for causal inference
B
A research project that follows the participants forward in time to identify future outcomes is referred to as
A)a cross-sectional.
B)a cohort study.
C)a case-control study.
D)a quasi-experimental
B
In a study looking at the correlation between annual income and cholesterol level, one concern was that the age of the participants might be a confounder because both income and cholesterol generally increase with age. Which of the following correlation methods could the researchers use to remove the influence of age on the correlation between income and cholesterol level?
A)Point-Biserial
B)Kendall's Tau
C)Spearman correlation coefficient
D)Partial correlation
D
Statistics use distinct symbols to represent specific information. Parameters are usually represented by
A)lowercase English letters.
B)lowercase Roman numerals.
C)owercase Roman letters.
D)lowercase Greek letters
D
Researchers conducting a study with ____ power have a _____ probability of committing a type ____ error.
A)high; low; II
B)low; high; I
C)high; low; I
D)low; high; II
D
The ______ of any statistical test represents the probability that the results were obtained by chance alone.
A)α-level
B)β-level
C)p-value
D)μ-value
C
A multivariate regression model looking at the association of intraocular pressure (mm hg) with (1) having seasonal allergies, (2) wearing contact lenses, and (3) using eye drops found a coefficient of determination (r2) of 0.23. How would you interpret this statistic?
A)seasonal allergies, contact lens use, and eye drop use taken together explain 23% of the variation in intraocular eye pressure.
B)The association between having seasonal allergies, use of contact lenses, and use of eye drops with intraocular pressure is not significant at the 0.05 level.
C)Those who wear contact lenses, have seasonal allergies, and use eye drops have a 37% chance of having high intraocular pressure.
D)The intraocular eye pressure of those who have seasonal allergies is 0.23 mm hg higher compared to those without allergies, adjusting for use of contact lenses and eye drops
A
The local health department is interested in determining if there is a difference in the incidence of childhood caries among children living in rural areas drinking untreated well water and children living in cities drinking fluorinated water. A null hypothesis could read
A)the oral health of the city children will be significantly worse than that of the rural children.
B)the oral health of the rural children will not differ from that of the city children.
C)the oral health of the rural children will be significantly worse than that of the city children.
D)the oral health of the city children will be significantly better than that of the rural children
B
A potential mistake when interpreting the data is to reject the H0 when it is true. This is referred to as
A)a type IV error.
B)a type I error.
C)a type II error.
D)a type III error
B
Researchers articulate the expected relationships between the variables by the _______.
A)statistic
B)null hypothesis
C)alternative hypothesis
D)parameters
B
The study plan hypotheses
A)will be changed as the study evolves.
B)must be very specific.
C)can be decided after the data are collected.
D)can be generalized
B
The _____ of a test is the probability that the test result and the diagnosis agree.
A)specificity.
B)predictive value.
C)efficiency.
D)sensitivity
C
In a study looking at the association of mean hours worked per day (hours) and age (years) with body mass index (BMI), the researchers used multivariate liner regression. The regression equation is below. What BMI would you predict from this equation for someone age 25 years who works 45 hours per week?
Y = - 3.95 + 0.04(hours worked) + 1.21(age)
A)66.05
B)28.1
C)32.05
D)-2.7
B
One response to the nursing shortage has resulted in the recruitment of nurses with various educational levels. The results of one research study found that the level of nursing education is critical in caring for certain patients. Therefore, we can conclude that
A)proper education results in better patient care.
B)increasing the number of nurses without concern for educational level has serious implications for critically ill patients.
C)proper mentoring will ensure the nursing staff is well prepared.
D)on-the-job training will provide adequate exposure to proper nursing techniques for all levels of patients
B
The researcher has determined the project has an α = 0.05. This indicates all values outside ____ will be rejected.
A)75%
B)45%
C)95%
D)55%
C
Under which of the following conditions would you need to use the Spearman correlation coefficient and not the Pearson correlation coefficient?
A)One variable on the ordinal measurement scale and one is on the interval measurement scale.
B)Neither variable is normally distributed.
C)There is only one variable to be examined.
D)The two variables are normally distributed.
E)
There are only three outliers.
F)The two variables do not have a linear relationship
ABEF
Confidence intervals can be computed around the population mean from a single simple mean using the
A)predictive value.
B)central limit theorem.
C)joint probability.
D)normal distribution
B
The alpha-level is defined by the researcher before any statistical tests are conducted. This specific level is defined as
A)the standard deviation.
B)error of inference.
C)statistically significant.
D)the p-value
C
Which of the following is not a part of the research project that is used statistically?
A)Interpretation of data
B)Peer review of data
C)Organization of data
D)Collection of data
B
Researchers rely on ________ to assist them in drawing meaningful conclusions on data collected on a population through their research project.
A)the probability theory
B)the empirical distribution
C)central limit theorem
D)the theoretical distribution
A
The probability that the laboratory test is positive when given to a group of patients who have the disease is referred to as
A)efficiency.
B)specificity.
C)sensitivity.
D)predictive value
C
A study looking at the correlation between cholesterol level and distance between home and work found a correlation coefficient of -0.13. How much of the variance in cholesterol level is explained by distance between home and work (ie, what is the coefficient of determination)?
A)0.17%
B)0.13%
C)13%
D)1.7%
A
The first step to deciding which statistical technique to use is
A)to identify the variables.
B)to determine which measurement scale to use.
C)to determine the hypotheses.
D)to identify the question to be answered
D
Health care practices have improved due in part to the use of
A)trial-and-error.
B)systemic review of research evidence.
C)observation.
D)experimentation
B
Techniques that allow conclusions to be drawn about the relationships found among different variables in a population sample are referred to as
A)inferential statistics.
B)explanatory statistics.
C)predictive statistics.
D)descriptive statistics
A
When determining the class intervals in creating a relative frequency chart, it is important to remember each class must be
A)mutually inclusive.
B)limited in number.
C)mutually exclusive.
D)broad in their width
C
Simple numerical or graphical summaries are referred to as
A)control statistics.
B)explanation statistics.
C)inferential statistics.
D)descriptive statistics
D
What is the difference between stepwise methods versus the standard approach and hierarchical methods of selecting independent variables to include in a linear regression model?
A)Stepwise is better for hypothesis testing than the other approaches because it is less influenced by chance.
B)Stepwise uses statistical criteria for selecting the variables to be included, whereas the other approaches use theoretical rational.
C)Stepwise methods allow you to include more variables without increasing the probability of making a type I error.
D)Stepwise uses theoretical rational, whereas the other approaches use statistical criteria for selecting the variables for inclusion
B
The hypotheses of the study should
A)be based on expert opinion.
B)be updated at the end of the study.
C)predetermine the study results.
D)state the expected relationship between the variables
D
The process for testing hypotheses includes which of the following?
A)Define significance level.
B)Compute the test statistic.
C)Compute the parameters that are being compared by the test statistic.
D)Obtain the p-value of computed statistic.
E)Make sure the data meet the necessary assumptions to compute the test statistic
ABCDE
The _______ can be used to test whether the sample mean is significantly different from a population mean.
A)one-sample z score
B)one-sample z-test
C)one-sample f-score
D)one-sample t test
B
How would you interpret a correlation coefficient of -1?
A)No correlation at all
B)Strong positive correlation—as one variable increases, so does the other
C)Perfect negative correlation—as one variable increases, the other variable decreases
D)Weak negative correlation—as one variable increases, the other variable decreases slightly
C
A research study needs to be well planned before starting. A common mistake seen in research is
A)reviewing existing literature on the subject.
B)developing a detailed study plan.
C)defining general and ambiguous terms or language.
D)failing to recognize approach limitations
D
Linear regression is appropriate for what type of dependent variable?
A)Ratio scale and normally distributed
B)Count
C)Dichotomous
D)Polytomous
A
A pediatrician will compare the 6-week-old infant with the accepted normal growth progress using the
A)frequency table.
B)percentile rank.
C)stemplots.
D)nominal scale
B
The normal distribution is a frequency polygon that demonstrates which of the following properties?
A)Mean, median, and mode are equal.
B)Bell shaped
C)Total area under the curve above the x-axis equals 1.
D)The population mean is shown as
ABC
In ________ probability, the distribution of events can be inferred without collecting data.
A)classical
B)relative frequency
C)theoretical
D)empirical
C
________ probability is the probability that one event will occur given that another event has occurred.
A)Addition
B)Joint
C)Conditional
D)Marginal
C
Which of the following are assumptions required for the Pearson correlation coefficient to be valid?
A)Homoscedasticity
B)The two variables must be normally distributed.
C)The two variables must be of ordinal, interval, or ratio measurement scale.
D)There are no outliers.
E)The two variables must have a linear relationship.
F)The two variables must be of interval or ratio measurement scale
ABCDEF
The marginal probability is computed by
A)the number of times the event occurred divided by the total number of times that it could have occurred.
B)dividing the subset by the total number of times and then multiplying by 100.
C)subtracting the number of times the event occurred from 100 and then dividing by the total number of times that it could have occurred.
D)the total number of times that the event could have occurred divided by the number of times the event occurred
A
A study that often attempts to understand how variables are related to each other is referred to as
A)descriptive statistics.
B)explanatory studies.
C)predictive studies.
D)inferential statistics
B
What do we mean by "regression toward the mean?"
A)The linear regression equation can be used to identify the average value of each variable in the model.
B)Linear regression normalizes the scale of the variables so they have a mean of zero and standard deviation of 1.
C)Outliers in the model should always be excluded when using linear regression.
D)The phenomenon that if a variable is extreme on its first measurement, it will tend to be closer to the average on a second measurement
D
What measure(s) of the strength and direction of association can we get from a linear regression model? (Select all that apply.)
A)Risk ratio
B)One-way ANOVA
C)Chi-square
D)Regression coefficient (beta)
E)F-statistic
F)Odds ratio
D
When defining a good research study, which of the following should be included?
A)Description of the planned statistical analysis
B)Statement of the problem
C)List of the hypotheses to be tested
D)Description of the sample and how it was obtained
E)The expected outcome
ABCD
A study was conducted looking at the association between number of polyps in the colon and mean grams of fiber consumed per day based on a standard food frequency questionnaire. The Pearson correlation coefficient was 0.9 with a p-value of 0.003 and the Spearman correlation coefficient was 0.28 with a p-value of 0.049. Which form of correlation would be more appropriate to report and why?
A)The Pearson correlation results should be reported because the two variables are normally distributed.
B)The Spearman correlation results should be reported because the p-value is closer to 0.05.
C)The Pearson correlation results should be reported because it shows a stronger correlation with a smaller p-value (more significant).
D)The Spearman correlation results should be reported because at least one of the variables does not meet the distribution assumption required to use Pearson correlation
D
What type of relationship between a dependent and independent variable is described by linear regression?
A)An exponential relationship
B)A parabolic relationship
C)A linear relationship
D)A threshold effect
C
Squaring the Pearson correlation coefficient (r2) tells us that
A)whether or not we need to conduct a Spearman test of correlation instead.
B)how much variance is shared by the two variables.
C)the direction of the association (positive or negative).
D)whether the correlation is statistically significant at the 0.05 level
B
Why is it important for the nurse to use evidence-based practice guidelines in the clinical setting?
A. to meet federal requirements
B. to attain credits towards promotion
C. to improve patient health outcomes
D. to follow state board of nursing procedure
C
Why is it vital for nurses to inform policy makers of current health care problems?
A. Legal issues can be prevented for patients.
B. Policies can be developed to resolve problems.
C. Policy makers can get more votes during elections.
D. Nurses can meet mandates of state boards of nursing
B
Which question can be answered using inferential statistics?
A. How many total subscribers do we currently have?
B. What percentage of our subscribers pay for their subscription using a credit card?
C. Which of two cover designs will result in a higher percentage of non-subscriber sales?
D. Has the number of subscribers to our publication increased or decreased over the last two years?
C
Which element should an effective study plan include?
A. why the study is important
B. a problem statement that is at least 5-6 sentences
C. personal opinion that is not backed up by evidence
D. details of the researcher's experience with previous studies
A
If a distribution is not symmetrical, which measure of central tendency is sensitive to outliers and skew-ness and thus, will not truly reflect the center of the data?
A. mean
B. mode
C. median
D. maximum
A
In statistics, which quantity is denoted by σ2
A. the sample variance
B. the population variance
C. the sample standard deviation
D. the population standard deviation
B
A study compares five different genotypes. Each genotype is coded with numbers, but the order is arbitrary and the computing of an average is meaningless.
Which type of measurement data was used?
A. ratio
B. interval
C. ordinal
D. nominal
D
A person wants to compare the average oxygen saturation for two patient groups.
Which measurement scale should be used for the data?
A. ratio
B. interval
C. ordinal
D. nominal
A
The frequency distribution of a data set is symmetric and the mean is 20.
Which statement is true about this data set?
A. The median is 10.
B. The median is 20.
C. The median is 40.
D. The standard deviation could be negative
B
At the age of one year, a child's height of 26 inches is at the 50th percentile according to a growth chart.
Which statement is true about this data?
A. At the age of two years, the height of the child will be 52 inches.
B. No conclusions can be drawn from the information that is provided.
C. Heights of children age one year were less than 26 inches in 50% of the population.
D. Heights of children age one year were less than 26 inches in 25% of the population.
C
Which symbol denotes a null hypothesis?
A. Hn
B. H0
C. Ha
D. Hr
B
Which statement is true about hypotheses?
A. The null hypothesis is the same as the research question.
B. Accept the null hypothesis when there is evidence supporting it.
C. The null hypothesis is rejected if the alternative hypothesis is accepted.
D. The alternative hypothesis is accepted if the p-value is sufficiently large
C
An experiment was conducted to determine whether a certain treatment method was effective in reducing dizziness. A test statistic result produced a p-value of 0.5.
Which statement is true about this situation?
A. The test results were statistically significant at a 5% level.
B. 50% of the test subjects experienced dizziness after the test.
C. Patients experienced 50% less dizziness as a result of the treatment.
D. The probability that one would obtain such a test statistic value by chance alone is 50%.
D
A study is conducted to determine if the patients who have one glass of green tea each day have a reduced healing time after a certain procedure.
Which statement describes a type I error in this scenario?
A. The study correctly concludes that the patients who have one glass of green tea each day have a reduced healing time.
B. The study incorrectly concludes that the patients who have one glass of green tea each day have a reduced healing time.
C. The study correctly concludes that the patients who have one glass of green tea each day do not have a reduced healing time.
D. The study incorrectly concludes that the patients who have one glass of green tea each day do not have a reduced healing time
B
A null hypothesis was not rejected, and later it was found that the results were false. This is an example of
Aa type I error.
B.a type II error.
C.a type III error.
D.a type IV error
B
The EPA claims that fluoride in children's drinking water should be at a mean level
of less than 1.2 ppm, or parts per million, to reduce the number of dental cavities. Identify the Type 1 error.
A) Fail to support the claim σ <1.2 when σ <1.2 is true.
B) Support the claim
μ <1.2 when
μ =1.2 is true.
C) Support the claim σ <1.2 when σ =1.2
is true.
D) Fail to support the claim
μ <1.2 when
μ <1.2 is true.
B
Which sample is appropriate for utilizing linear regression?
A. a nonrandom sample of 50 diabetes patients in Texas
B. a random sample of 10 patients in a 1000-bed hospital
C. a nonrandom sample of 1000 people in the United States
D. a random sample of 30 nurses in a hospital unit of 90 nurses
D
Under which of the following conditions would you need to use the Spearman correlation coefficient and not the Pearson correlation coefficient?
A)The two variables are normally distributed.
B)The two variables do not have a linear relationship.
C)One variable on the ordinal measurement scale and one is on the interval measurement scale.
D)There are only three outliers.
E)Neither variable is normally distributed.
F)There is only one variable to be examined
BCDE
Which Pearson correlation coefficient has the smallest strength of association?
A. -0.9
B. -0.7
C. 0.5
D. 0.3
D
Consider the relationship between two continuous variables and the two-dimensional scatterplot associated with these variables. If the correlation coefficient is -1, then
A. All points lie in a straight line with a slope of -1.
B. All points lie in a straight line with an unknown negative slope.
C. All points do not lie in a straight line but the best fitting regression line has a slope of -1.
D. There is a strong positive relationship between these two variables
B
In a study of the effect of smoking on lung cancer, it is estimated that the odds ratio (for a subject that smokes relative to a subject that does not smoke) is 2.6. This means that:
A. A person with lung cancer is 2.6 times as likely to be a smoker as a non-smoker.
B. A person that smokes is 2.6 times as likely to develop lung cancer as a person that does not smoke.
C. A person that smokes has a 2.6% higher chance of developing lung cancer than a person that does not smoke.
D. Lung cancer increases the prevalence of smoking by 2.6%.
B
You are reading a journal article and you see a p-value of 0.11. Which of the following are true?
A. Since the p-value is not significant, there is no need to investigate further.
B. You should determine to what hypotheses the p-value corresponds so that the result can be put into context.
C. P-values are sensitive to sample size and thus you should determine upon what sample size the p-value is based.
D. B and C
D
Healthcare Statistics may be used to:
A. Describe the results of medical, public health, environmental, and ecological studies
B. Isolate and estimate the effect of new treatment modalities while controlling for other important variables and identify risk factors for various diseases and syndromes
C. Make decisions about public health policy and plan for new treatments and interventions
D. All of the above
D
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